Add CMake config to build benchmarks (aws#2582)

* Fix some minor issues in existing benchmarks
* Use feature probing for __restrict__

CMakeLists.txt

@@ -148,6 +148,14 @@ try_compile(
         COMPILE_DEFINITIONS "-Werror"
 )
 
+# Determine if __restrict__ is available
+try_compile(
+        __RESTRICT__SUPPORTED
+        ${CMAKE_BINARY_DIR}
+        SOURCES "${CMAKE_CURRENT_LIST_DIR}/tests/features/__restrict__.c"
+        COMPILE_DEFINITIONS "-Werror"
+)
+
 if(APPLE)
     set(OS_LIBS c Threads::Threads)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
@@ -229,6 +237,10 @@ if (FALL_THROUGH_SUPPORTED)
     target_compile_options(${PROJECT_NAME} PUBLIC -DS2N_FALL_THROUGH_SUPPORTED)
 endif()
 
+if (__RESTRICT__SUPPORTED)
+    target_compile_options(${PROJECT_NAME} PUBLIC -DS2N___RESTRICT__SUPPORTED)
+endif()
+
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules)
 
 find_package(LibCrypto REQUIRED)
@@ -293,8 +305,30 @@ if (BUILD_TESTING)
     target_include_directories(s2nd PRIVATE $<TARGET_PROPERTY:LibCrypto::Crypto,INTERFACE_INCLUDE_DIRECTORIES>)
     target_include_directories(s2nd PRIVATE api)
     target_compile_options(s2nd PRIVATE -std=gnu99 -D_POSIX_C_SOURCE=200112L)
+
+    if(BENCHMARK)
+        find_package(benchmark REQUIRED)
+        file(GLOB BENCHMARK_SRC "tests/benchmark/*.cc")
+        enable_language(CXX)
+        foreach(benchmark ${BENCHMARK_SRC})
+            string(REGEX REPLACE ".+\\/(.+)\\.cc" "\\1" benchmark_name ${benchmark})
+            add_executable(${benchmark_name} ${benchmark})
+            target_include_directories(${benchmark_name} PRIVATE api)
+            target_include_directories(${benchmark_name} PRIVATE tests)
+            target_link_libraries(${benchmark_name} PUBLIC ${PROJECT_NAME} testss2n benchmark::benchmark)
+
+            # Based off the flags in tests/benchmark/Makefile
+            target_compile_options(${benchmark_name} PRIVATE -pedantic -Wall -Werror -Wunused -Wcomment -Wchar-subscripts
+                    -Wuninitialized -Wshadow -Wcast-qual -Wcast-align -Wwrite-strings -Wno-deprecated-declarations
+                    -Wno-unknown-pragmas -Wformat-security -Wno-missing-braces -fvisibility=hidden -Wno-unreachable-code
+                    -Wno-unused-but-set-variable)
+        endforeach(benchmark)
+
+    endif()
 endif()
 
+
+
 #install the s2n files
 install(FILES ${API_HEADERS} DESTINATION "include/" COMPONENT Development)
 

s2n.mk

@@ -178,6 +178,12 @@ ifeq ($(TRY_COMPILE_FALL_THROUGH), 0)
 	DEFAULT_CFLAGS += -DS2N_FALL_THROUGH_SUPPORTED
 endif
 
+# Determine if __restrict__ is available
+TRY_COMPILE__RESTRICT__ := $(call try_compile,$(S2N_ROOT)/tests/features/__restrict__.c)
+ifeq ($(TRY_COMPILE__RESTRICT__), 0)
+	DEFAULT_CFLAGS += -DS2N___RESTRICT__SUPPORTED
+endif
+
 CFLAGS_LLVM = ${DEFAULT_CFLAGS} -emit-llvm -c -g -O1
 
 $(BITCODE_DIR)%.bc: %.c

tests/benchmark/s2n_base64_benchmark.cc

@@ -41,7 +41,7 @@ class TestFixture : public benchmark::Fixture {
         rc = s2n_blob_init(&r, pad.data(), pad.size());
         assert(rc == 0);
 
-        result  = s2n_get_urandom_data(&r);
+        result  = s2n_get_public_random_data(&r);
         assert(s2n_result_is_ok(result));
         rc = s2n_stuffer_alloc(&entropy, pad.size());
         assert(rc == 0);

tests/features/__restrict__.c

@@ -0,0 +1,27 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+void swap(int *__restrict__ left, int *__restrict__ right) {
+    int temp = *left;
+    *left = *right;
+    *right = temp;
+}
+
+int main() {
+    int a = 1, b = 2;
+    swap(&a, &b);
+    return 0;
+}
+

utils/s2n_ensure.h

@@ -67,4 +67,20 @@
     }                                                                            \
   } while(0)
 
+/**
+ * `restrict` is a part of the c99 standard and will work with any C compiler. If you're trying to
+ * compile with a C++ compiler `restrict` is invalid. However some C++ compilers support the behavior
+ * of `restrict` using the `__restrict__` keyword. Therefore if the compiler supports `__restrict__`
+ * use it.
+ *
+ * This is helpful for the benchmarks in tests/benchmark which use Google's Benchmark library and
+ * are all written in C++.
+ *
+ * https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html
+ *
+ */
+#if defined(S2N___RESTRICT__SUPPORTED)
+extern void* s2n_ensure_memcpy_trace(void *__restrict__ to, const void *__restrict__ from, size_t size, const char *debug_str);
+#else
 extern void* s2n_ensure_memcpy_trace(void *restrict to, const void *restrict from, size_t size, const char *debug_str);
+#endif